When Will Extreme Heat Become Unlivable?

[Uncle Joe]

Jun 18, 2025

Heat is the deadliest weather hazard in the U.S. and many places around the world, and it's only getting worse.
The most deadly heat waves so far have been dry heat waves. But a new threat is rising: humid heat waves, aka wet-bulb events. Scientists have identified wet-bulb temperatures where sweat can’t evaporate fast enough to cool the human body. And once this threshold is crossed, it doesn’t matter how much shade or water you have: you won’t survive without environmental cooling like air conditioning.
In this episode of Weathered, we break down: What wet-bulb temperature actually means, why it’s so dangerous, what areas will be affected, and why air conditioning, while essential, isn’t enough.

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